Fluid transmission



My 239 19%. T. H. THOMPSQN www@ FLUID TRANSMISSION Filed Oct. 28, 1944 3Sheets-Sheet l mme@ July 23, 1946 I T. H. THOMPSON FLUIDTfw.Ns1\/1IssIoNy 5 Sheets-Sheet 2 Filed Oct. 28, 1944 my 23 i945 T. H.THOMPSON FLUID TRANSMISS ION Filed'oct. 2a, 1944 s sheets-sheet sPatented July 23, 1946 UNITED STATES FLUID TRANSMISSION Tom H. Thompson,Mamaroneck, N. Y., assignor to Thompson-Wade Corporation,

Detroit,

Mich., a corporation of Michigan Application October 28, 1944, SerialNo. 560,896

18 Claims.

This invention relates to fluid transmissions and it is an object ofthis invention to provide a fluid transmission of an improvedconstruction, compact, reliable and of a weight suitable for use inmotor vehicles. It is also an object of this invention to provide aiiuid transmission in which the maximum iiuid pressure is held with in apredetermined limit and in which the fluid pressure and liquid volumesupplied is automatically adjusted to the motor requirements.

In the drawings in which a preferred construction of the invention isillustrated;

Fig, 1 is a longitudinal sectional view of a fluid transmission inaccordance with this invention, the parts being shown in the neutral orinactive position;

Fig. 2 is a view similar to Fig. 1 with the parts shown in the'positionfor reverse operation; and

Figs. 3 and 4 are transverse sectional views taken as on lines 3-3 and 44, respectively, of Fig. 1, parts being omitted in order to show theports and passages more clearly.

In the drawings the invention is shown in connection with a transmissionsuitable for use onI motor vehicles.

As shown in the drawings a iud transmission in accordance with thisinvention comprises a cylindrical casing I rotatably mounted in suitablebearings 2 supported from members 5 carried by the vehicle'frame (notshown). The casing i is arranged to rotate about its longitudinal axisbut is limited to rotation in one direction, the direc-y tion of enginerotation, by means or an over-running clutch 4 adapted to engage thecasing I and a member attached to the vehicle frame. At one end thecasing I is formed with a plurality of pump cylinders 8 spaced uniformlyabout the casing I and having pump pistons I5 therein while at itsopposite end the casing I is formed with a plurality of motor cylindersI2 having the motor pistons I4 therein. Preferably there are the samenumber ofrmotor cylinders as pump cylinders and for the purpose ofillustration in the drawings the casing I is shown as formed with vecylinders at each end of the casing.

Rotatably mounted in the pump end of the casing I is a substantiallytubular member I5 which extends inwardly for about a half of the lengthof the casing I and is provided at its inner end with a flange Il whichis engaged by an overrunning clutch I8 with'a co-operating flange I9 ofa substantially tubular member 20 journalled in the motor end of `.thecasing I and terminating in a solid portion forming a drive shaft 2l.The clutch IB is arranged to prevent the member 20 rotating at a greaterspeed than the -member I6 While permitting the member I6 to rotate morerapidly than the member 20.

The casing I is` provided with a chamber 22 which is in opencommunication with the cen-` tral portion of each pump cylinder 8 andwith a second chamber 24 in open communication with the central portionof each motor cylinder I2. Projecting into the chamber 22 from oppositesides of the member I6 are rotatable pivots 26 to which is fixed anannular disk 28 which surrounds the member I6. The disk 28 Vis recessedon'its perimeter to receive roller bearings 30 on which is mounted aring 32 having luniformly spaced radially projecting pins 33, therebeing a pin 33 for each pump piston I0. Collars 34 rotatably mounted onthe pins 33 have projections 35 to which are pivotally connected ends oflinks 36 the other ends of which are pivotally connected to the pumppistons I0. Secured to the member 20 at a iixed inclination to the axisthereofV is a disk 38 having rotatably'mounted thereon a ring 39 havingpins 40 connected by links 42 4to the motor pistons I4 in a mannersimilar to the connection of the pins 33 to the pistons I0.

The tubular member I 5 projects beyond the pump end of the casing I andis provided With a collar or flange 43 adapted to be connected by anoverrunning clutch 44 to a member 45 carried by the vehicle frame, theclutch 44 limiting the tubular member I6 to rotation in one direction.The interior of the tubular member I6 is provided with a threaded collar46 in which is engaged a tubular member 41 having a right hand threadengaged with the collari46 and a flanged inner end to which is securedone end of a spring 48, the other end of whichis secured to an inwardlyprojecting collar 49 on the tubular member I5. The outer face of theother end of the member l 41 is shaped to form splines 50 which areslidably engaged with the correspondingly shaped inner face of theadjacent end of a tubular member 52, the other end of which 'is ofgreater diameter and shaped, as at 53, to form a clutch member adaptedto engage with a clutch member 54 driven from a suitable source of power55.

The member 52 is grooved, asat 56, for engagement by a shift lever 51which is pivotally mounted, as at 58, and serves to shift 'the member 52into and out of engagement with the clutch member 54. The member 52 isfreely slidable on the member 4l and in the closure 59 :at the end ofthe tubular member I6.

Mounted in the tubular member 52 and secured therein by a ring 60secured to the `member 52 so as to be reciprocated with the member 52 isa tubular member 62 having its outer end enlarged and shaped, as at B3,to form a clutch 55 member adapted to engage with a clutch member 64driven from the source of power 55. The clutch members 53, 54 and 63,64are so positioned and arranged that only one pair of the clutchmembers can be engaged at a time, the diierent pairs of the clutchmembers being engaged by movement of the lever 51 in oppositedirections. The inner end of the member 62 is slidably splined to an endof Va tubular member 65 rotatably mounted in the member 41 and having aleft hand thread 66 engaging with a corresponding thread on the innerface of the member 41. u n extends inwardly beyond the collar 49 on themember I6 and at its innern endis providedwith. a fiange 61 which formsa seat for a spring clusterr 68 secured in an annular chamber inal'cup'- shaped member 69 having a central stem 10 extending in oppositedirections fromthe member 69. The annular chamber inthe member 69 isclosed by a ring 69a screwed into the member 69 and serving to hold thevmember 65 engaged with the member 69' and the spring cluster 68 underan' initial loading of 1800 pounds. The stem 19, in one direction,projects into' the tubular member 65' and aidsin supporting the member69'. TheA extension ofthe stem 1D in the opposite direction hasYjournaled thereon adjacent its free end a ring 12having projecting lugs13 to which one Vend of links14'are pivotallyconnected. The other endsof the linksv 14 arepivotally connected to the outer endsof the arms15-flxed to the pivotal supports 26for the'disk 28'.

The casingl is providedA with passages 13- positioned` between the pumpcylindersi and' the motorcylinders' I2 and connecting theY chambers22'and 24. A passage-19 extends -irom the'inner end of each pumpcylinder 8^ to the chamber in which the tubularA member I6 rotates and apassage 39 extends from outer" end of each pump cylinder Sto thesamechamber. Ports 82 and 83 Vin the tubular member I6 control theconnection of the passages 19 and 80, respectively', to the interiors ofthe tubular members I6 and 29;'the passages 19 and 80 havingopenings'extending approximately 60- aboutthe faceof the chamber and theports 82- and83A extending approximately 120" on the face of the tubularmember I6 so that Veach passage is open to the-interior ofthe tubularmember I6 throughout substantially a halfrevolution of the tubularmember I6; The ports 82 and 88 are `positionedso that one passage 19 or80 is closedwhen the other passage is open. Branch passages 84 and 85extend from passages 19 and 89, respectively, and are connected tochamber 22 by ports 86 and 81, respectively, in iianges or collars 88and 89, respectively, projecting from thetubular member I6. The passages84 and 85 also extend through an arc of approximately 60 and the ports86 and 81 extend through an arc of 120 so as to establish connectionwith the chamber 22 during a half revolution of the tubular member I6,one passage 84 or 85 being closed while the other passage is open. Ports82 and 83 and ports 86 and 81 are so related that one end of a pumpcylinder is connected to the interiory of the tubular member I6 Whilethe opposite end of that pump cylinder is connected to the chamber 22and the ports in the tubular member I6 are so positioned with respect tothe pivots 26 sup- The member 65 i porting the disk 28 that theconnections estab- 4 nected by ports 91 and 98, respectively in flanges99 and |89, respectively, on the tubular member 29. The ports'andpassages ofthemotor end of the casing I correspond in size and positionto the ports and passages at the pump end of the casing so that one endof a motor cylinder is connected to the interior of the tubular member29 during a half revolution of the member 26 while thev opposite end ofthat motor cylinder is con nected to the chamber 24 and the change intheV fluid connections each half-revolution of the member ZIandfdisk 38causes a change in the end of the motor piston I4 to which the operatingpressure is applied.

The flange 89 of the tubular member I6 is provided with a passage |02-constantly opento the interior ofthe tubular member I6 and extending tothe interior of an expandible member |93 secured to the adjacent faceslof the flange B9 and the disk 28 so as to subject a definite area of thedisk 28 to the pressure of the iluid in the interior of the tubularmembers I6 and 29.-

The casing I at one end is formed with a circle of recesses |04 adaptedto receivek a locking plunger mounted in the member 6 and normally heldretracted by a spring I 96. The `plunger |95 is operated to engage in arecess |04 and prevent rotation of the casing I in either: directionwhen the lever 51 is operatedto the reversei position, the lever 51being connected to. a link |91 which is connected to a lever |68 mountedon the member 6 -in position to engage theiplunger |95. A pin and slotconnection betweenthe lever 51 and link |91 permits the. lever 51 beingoperatedv to the forward position without operating the plunger |05.

In the operation of the device, the sourceof power being operating androtating theA clutch members 54 and 64, moving the operating lever 51 tothe right to the forward positionshiftsthe member 52 to engage theclutch member 53. and 54 and causing the members 52 and 41 to berotated. Rotating the member 41 causes the member 41 to be shiftedlongitudinally (to the righi-,iin Fig. l), owing to its right-handthread connection with the member I6, compressing thespring 48 andincreasing the resistance` to the movement of the member 41 in thememberl. The spring 48 may be designed to be compressed'solidby apressure of approximately 350 pounds. The resistance to the rotation ofmember' 41inmember I9 eventually becomes suicient to cause member I6 torotate with member 41 and rotate the diskv28. Movement of member 41 tothe right hascarried with it the members (i5V and 69 causing the disk 28to be tilted from therpo'sition shown in Fig. 1 so that rotation of thedisk 28' causes reciprocation of the pump pistons I9. Rotation oi thecasing I in the reverse direction at this time is prevented by theclutch 4. Asf shown, the ports and'passages are so arrangedv thatoperation of the pump pistons when the lever 51 is in the forwardposition will cause the discharge of uid under pressure to the interiorsof the tubular membersA I6 and 28 and thence to the motor cylinders tooperate pistons I4 and fluid will be discharged from the motor cylindersto the chamber 24, passing through passages 18 to chamber 22 and then tothe pump cylinders. vOperation of the pump pistons. III by the rotationof the disk 28 accordingly builds up fluid pressure in theinteriors ofthe members I6 and 29 and against the motor pistons I4, the pressurebeing builtup in accordance with'the resistance oii'ered tothe vrotationof the shaft2| and disk 38. The pressure in the tubular members I6 and28 is also applied to the disk 28 through the passage |82 and member |83in a direction to shift the disk 28 so as to reduce the stroke of thepump pistons from their maximum stroke but this movement of the disk 28is yieldin-gly resisted by the springs 68, member 65 being held by itsthreaded connections through member 41 with the member I6.

As the resistance to the movement of the motor pistons I4 decreases, therate of movement of the pistons I4 will increase and the fluid pressureacting against the disk 28 will decrease permitting the spring 68 togradually increase the tiltof the disk 28 until the pump pistons I0 areagain operating at maximum stroke. The balancing of the fluid pressureagainst a predetermined spring pressure provides an automatic controlwhich insures the maintenance of a supply of fluid at maximum pressuredelivered to the motor in a volume in accordance with the instantaneousrequirements of the motor. The transmission is thus able to cover theentire range to maximum torque requirement in steps of innitesimalmagnitude While remaining instantaneously responsive to variations-intorque demand.

By having the volumetric capacity of the pump greater than thevolumetric capacity of the motor, the motor eventually tends to rotatethe tub-ular member 2i) and shaft 2| faster than the speed of rotationof the tubular member I6 but such greater speed on the part of themember is prevented by the engagement of the over-running clutch I8.

Whenthe clutch I8 engages, theV transmission may be'said to be in directdrive a condition in which the entire transmission, including thecassion the lever 51 is moved forward to the reverse position shiftingthe member v'52 away from the clutch member 54 and carrying the member62 to the right, as shown in Fig. 2, to engage the clutch members 63 and64. With the clutch members 83 and 84 engaged the members `62 and 65will be rotated in the same direction as was the member 52 but the lefthand thread connection of the member 65 with the member 41 will causethe member 65 to be shifted to the left as it is rotated, drawing withit the member 69 and its stem 10 and through links 14, arms 15 andpivots 26, tilting the disk 28 in the opposite direction until furtherVtilting movement of the disk is prevented by the stop IIB." 'Thistilting movement of the disk 28 effects a movement "of the pump pistonsIEI and changes the relation of the disk 28 and pump pistons I8 withrespect to the valve ports 82, 83 and 86, 81 so that the pump pistons I0now discharge fluid under pressure to the chamber 22 and throughpassages 18 to chamber 24 and then to` the motor cylinders `while fluidis supplied to the pump cylinders from the interior of the tubularmembers I6 and20. As the relation of the disk 38 and the tubular member28 is not changed reversing the tilt of the disk 28 causes a reversal inthe operation of the motor pistons I4 and the rotation of the disk 38and tubular member2Il and shaft' 2|.

Whatis claimedis:

1. In a iluid transmission, a casing, pump plstons `mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for relative rotation of said disk and pistons comprisingmeans connecting said disk and its supporting means permitting variationof the inclination of the plane of said disk relative to the axes ofsaid pistons, means operatively connecting said `disk and pump pistonsto reciprocate said pistons upon relative rotation of said disk andpistons and driving means for relatively rotating said disk and pistonscomprising means responsive to the resistance to said relative rotationfor selectively inclining the plane of said disk relative to the axes ofsaid pistons.

2. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for relative rotation of said disk and pistons compricingmeans connecting said disk and its supporting means permitting variationof the inclinaton of the plane of said disk relative to the axes of saidpistons, means operatively connecting said disk and pump pistons toreciprocate said pistons upon relative rotation of said disk andpistons, driving means for relatively rotating said disk and pistonscomprising means responsive to the resistance to said relative rotationfor selectively inclining the plane of said disk relative to the axes ofsaid pistons.

3. In a fluid transmission, a casing, pump pistons mounted forreciprocation insaid casing, a disk'in said casing, means supportingsaid disk for relative rotation cf said disk and pistons comprisingmeans connecting said disk and its supporting means permitting variationof the inclination of the'plane of said disk relative to the axes ofsaid pistons, means operatively connecting said disk and pistons toreciprocate said pistons upon relative rotation of said disk andpistons, driving means for relatively rotating said disk and pistonscomprising means responsive to the resistance to rotation of said diskfor inclining the plane of said disk relative to the axes 0f saidpistonsand means to apply the fluid pressure generated by said pumppistons for changing the inclination of said disk to reduce the strokeof said pump pistons.

4. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for relative rotation of said disk and pistons comprisingmeans connecting said disk and its supporting means permitting variationof the inclination of the plane of the disk relative to the axes of saidpistons, meansoperatively connecting said disk and pistons toreciprocate said pistons upon relative rotation of said disk and fpistons, driving means for relatively rotating said disk and pistonscomprising means responsive to the resistance to 'rotation of said diskfor inclining the plane of saidY disk relative to the axesof saidpistons and means to apply fluid pressure generated by said pump in adirection to reduce the inclination of the plane of said disk.

5. In a fluid transmission, a casing, pump pistons mounted Vforreciprocation in said casing, a disk in said casing, means supportingsaid'disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said diskand drive means for rotating said disk, said drive means havingselectively operated means responsive to the resistance to rotation ofsaid disk for moving said disk about said second yaxis upon operation ofsaid drive-means to rotate said disk. i

6. In a fluid transmission, a casing, pump pistons'mounted forreciprocation in said casing, a disk in said casing, means supportingsaiddisk for rotary movement and' movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of'sa'id diskand selectively operated drive means for rotating said disk, saidA drivemeans comprising engaging co-afxiall members relatively shifted bythe'resistance to rotation of said disk to move said disk about saidsecondV axis upon operation'of said drive means to rotate said disk.

7. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for rotary movement and movement aboutv a second axisat anangle to the axis of rotation, meansoperatively vconnecting said diskand pistonsfor reciprocating said pistons upon rotation of said diskvand drive means for rotating said disk, said drive means comprisingengaging coaxial members, means for relatively shifting said co-ax-ialmembers to move said disk about said second axis upon operation of saiddrive means to-rotate said disk and means yieldingly opposing saidrelative movement of said co-axiai members upon operation of said drivemeansA to, rotate said disk.

8. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for rotary movement andmovement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand, pistons for reciprocation said pistons upon rotation of said diskand drive means for rotating said disk, said drive means comprisingengaging coaxial members, means forY relatively shifting said co-axialmember to move saiddisk about said second axis upon operation of saiddrive means to rotate said disk and a spring means opposing saidrelative movement of said co-axial meinbers upon operation of said drivemeans to rotate said disk, said spring means operating to return saidco-axial members to their initial positions upon the Withdrawal of the'driving power from said drive means.

9. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, meanssupportingsaidV disk for rotary movement and movement about ai second axis at anangle to the axis of rotation,

.means operatively connecting said disk and pistons for reciprocatingYsaid pistons upon rotation of said disk and drive means for rotatingsaid disk, said drive means comprising a pair of power Vreceivingmembers, co-axial members operated means] operatively'coiinectin'gjsaid' `disk a'r'idfpi's- 8 tons for reciprocating saidpistons upon rotation of saidl disk and drive means vvfor rotatingV saiddisk, said drive means comprising tubular means threaded intossaid disksupporting means, power receiving means adapted to rotate said tubularmeans, yielding .means opposing relative movement of said tubular meansand. said disk supporting means upon operation oiv said .power receivingmeans to rotate said disk and means connecting said tubular means anddisk to move said disk aboutsaid second axis upon relative movement ofsaid tubular means and `said disk sup-v porting means. Y

1l. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a. disk in said casing.,v means supportingsaid disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said disk'andi pistons for reciprocating said pistons upon rotation of said disk,drive means for rotating said disk and means for applying fluid pressuregenerated by said pistons to move said-disk about said second axis, saiddrive means comprising tubular means threaded into said disk supportingmeans, power receiving means adapted to rotate said tubular means,`yielding means opposing relative movement of said tubular means and saiddisk supporting means upon operation of said power .receiving means torotate said disk and means connecting said Ytubular means and disk tomove said disk about said second axis upon relative movement kof saidtubular means and saidl disk supporting means, said connecting meanshaving yielding means opposing .movement of said disk by the lfluidpressure. e

12. In a iiuid transmission,` a casing, pump Ypistons mounted forreciprocation in said casing,

a disk in said casing; means supporting said disk for rotary movementand movement about a second axis at an angle to the axis of rotation,means operatively connecting said disk and pistonsfor reciprocating saidpistons upon rotation ofsaid disk, drive means for rotating said disk,said drive means having means responsive to the resistance to rotationof said disk for Vmoving said disk about said second axis upon operationof said drive means to rotate said disk, a second diskV in said casing,means rotatably'supporting said second disk, motor` pistons mounted forre'- ciprocation in said casing, means connecting said motor pistons andsaid second disk t'o rotate said second'diskV upon reciprocation of saidmotor pistons, said casing having passages for the supply of fluid underpressure between said resistance to rotation of said disk for movingsaid disk about said second axis upon operation of saiddrive means torotate said disk, a second disk in said casing, means rotatablysupporting Vs'aid secondv disk, motor pistons mounted forreciprocation'in said casing, means connecting' said' motor pistons and'said second disk to rotate said second disk upon reciprocation of said'motor pistons, said casin'ghavi-ng Vpassages."for the supply of uidunder pressure between said pump and motor pistons, ports in said disksupporting means controlling said passages and clutch means connectingsaid disk supporting means and preventing said second disk supportingmeans from rotating faster than said first disk supporting means.

14. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said disk,drive means for rotating said disk, said drive means having meansresponsive to the resistance to rotation of said disk for moving saiddisk about said second axis upon operation of said drive means to rotatesaid disk, a second disk in said casing, means rotatably supporting saidsecond disk, motor pistons mounted for reciprocation in said casing.means connecting said motor pistons and said second disk to rotate saidsecond disk upon reciprocation of said motor pistons, said casing havingpassages for the supply of fluid under pressure between said pump andmotor pistons and ports in said disk supporting means controlling saidpassages, said driving means for said first disk comprising means forvarying the relation of said pump pistons and said first disk to theports in said first disk supporting means to effect a reversal ofrotation of said second disk.

15. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said disk,drive means for rotating said disk, a second disk in said casing, meansrotatably supporting said second disk, motor pistons mounted forreciprocation in said casing, means connecting said motor pistons andsaid second disk to rotate said second disk upon reciprocation of saidmotor pistons, said casing having passages for the supply of fluid underpressure between said pump and motor piston and ports ,in said disksupporting means controlling said passages, said drive means for saidfirst disk having selectively operated means responsive to theresistance to rotation of said disk for rotating said disk about saidsecond axis to reverse the direction of rotation of said second disk.

16. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means sup-portingsaid disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said disk, adrive means for rotating said disk supporting means and disk comprisingmeans for rotating said disk in one direction about said second axis, asecond drive means for rotating said disk supporting means and diskcomprising means for rotating said disk in the opposite direction aboutysaid second axis, a second disk in said casing, means rotatablysupporting said secl0 ond disk, motor pistons mounted for reciprocationin said casing, means connecting said motor pistons and said second diskto rotate said second disk upon reciprocation of said motorpistons,.said casing having passages for the supply of uid between saidpump and motor pistons,l said disk supporting means having portscontrolling said passages and said second disk changing its direction ofrotation upon a change in the driving means for said first disk.

17. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supporting`said disk for rotary movement and movement about a secand axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said disk,drive means for rotating said disk, said drive means having meansresponsive to the resistance to rotation of said disk for moving saiddisk about said second axis upon operation of said drive means to rotatesaid disk, a second disk in said casing, `means rotatabls7 supportingsaid second disk, motor pistons mounted for reciprocation in saidcasing, means connecting said motor pistons and said second disk torotate said second disk upon reciprocation of said motor pistons, saidcasing having passages for the supply of fluid under pressure betweensaid pump and motor pistons, ports in said disk supporting meanscontrolling said passages, clutch means connecting said disk supportingmeans and preventing said second disk supporting means from rotatingfaster than said first disk supporting means and clutch means preventingrotation of said casing in a direction opposite to the direction ofrotatien of said iirst disk While permitting rotation of said casing inthe direction of rotation of said first disk.

18. In a fluid transmission, a casing, pump pistons mounted forreciprocation in said casing, a disk in said casing, means supportingsaid disk for rotary movement and movement about a second axis at anangle to the axis of rotation, means operatively connecting said diskand pistons for reciprocating said pistons upon rotation of said disk, adrive means for rotating said disk supporting means and disk comprisingmeans for rotating said disk in one direction about said second aids, asecond drive means for rotating said disk supporting means and diskcomprising means for rotating said disk in the opposite direction about`saisi second axis, a second disk in said casing, means rotatablysupporting said second disk, motor pistons mounted for reciprocation insaid casing, means connecting said motor pistons and said second disk torotate said second disk upon reciprocation of said motor pistons, saidcasing having passages for the supply of fluid between said pump andmotor pistons, said disk supporting means having ports controlling saidpassages and said second disk changing its direction of rotation upon achange in the driving means for said rst disk, clutch means preventingrotation of said casing in a direction opposite to the rotation of saidrst disk while permitting rotation of said casing in the direction ofrotation of said rst disk when said iirst drive means is operated andmeans preventing rotation of said casing when said second drive means isoperated.

TOM H. THOMPSON.

